Motivational Interviewing (MI) is a directive, client-centered therapeutic method employed in the treatment of substance abuse. There is a broad evidence base for MI and several hypothesized mechanisms of action have been tested;however, none has survived empirical scrutiny. One recently proposed mechanism of action for which support does exist is change talk, which is defined as in-session verbal commitments by clients to change their problem behavior. The concept of change talk fits well with MI's basis in social cognition, in particular the notion of self-perception. MI maintains that during addiction treatment clients essentially talk themselves into change. Recent work has shown that therapist speech affects the probability that clients will emit change talk during a session. The frequency and strength of these change talk utterances from as early as the first MI treatment session have been shown to predict substance use outcomes in both drug abuse and problem drinking. Although the ability of therapists to elicit change talk from clients, and the relationship between change talk and outcome, are both established, the neural substrate of change talk remains uncharted. This application was designed in order to explore this neural substrate, in response to NIDA program announcement 07-227, "Neuroscience Research on Drug Abuse." The human mirror neuron system is a strong candidate for this neural substrate. Active during both the observation and performance of actions, as well as in empathy and affect, this system is believed to underlie our ability to understand both other people and ourselves. This relationship with social cognition, together with its involvement in language processing, suggest the mirror neuron system as an ideal candidate for investigating the brain processes engaged in change talk. Capitalizing upon the excellent spatiotemporal resolution of magnetoencephalography (MEG) to explore these processes, we will explore the neural substrate of client change language by measuring brain responses to brief utterances of client's own change talk and sustain talk recorded during an MI session, as well as responses to utterances of the subcategories of commitment and preparatory language, in a sample of ambivalent marijuana and alcohol users. This sample of ambivalent substance users is the population for which MI is designed, and in which it is most effective. We will use anatomical magnetic resonance imaging (MRI) scans to co-localize the activity detected with MEG. In this way, we can explore differences between change talk and sustain talk, differences between the subcategories of commitment and preparatory language, as well as test the hypothesis that this activity will localize to the mirror neuron system. This study will allow us to pinpoint the brain locations and dynamics of the neural mechanisms active in change talk, and to use this information to initiate a body of research on the neurophysiological basis of the therapeutic process in MI. In the long term this information could be used to develop refinements to motivational interviewing, target the salient regions and processes more precisely in order to achieve the most efficient and powerful expressions of change talk, which could ultimately lead to improved substance abuse outcomes. PUBLIC HEALTH RELEVANCE: PROJECT NARRATIVE Motivational Interviewing (MI) is a treatment that has been shown to help drug and alcohol users reduce or stop their substance abuse. Although we know that this complex treatment is helpful, we do not yet know why it works. This project focuses on investigating one proposed active ingredient in MI: client change talk, a special type of language that clients use during MI treatment sessions indicating their desire, ability, reason, or need to change. Investigating the brain processes that underlie change talk in MI will improve our understanding of why MI works and could allow us to refine the technique to employ this method more efficiently, which could potentially translate into substantial savings in public health dollars.